Some operation from BA control panel results in "Service Unavailable" error

Symptoms

Some operation from BA control panel results in Service Unavailable error. It can be any kind of operation - subscriptions synchronization, downloading of some big PDF document, accessing TTS ticket queue, etc

Cause

Service Unavailable error does not mean an exception from application side, it is apache timeout. An error means that an operation took more time than default timeout specified in httpd configuration.

Resolution

Check if is is ok that an operation takes more time than apache timeout. If there are reasons (huge set of data for example), timeout can be adjusted.

Check that you are on a correct host (OA UI or Branding, NG), in /var/log/httpd/error_log there shall be a record similar to